00:01
Okay, we've got an apple dropped from a bridge, and then another apple is thrown down from the same height.
00:19
So i need to look at the graph.
00:24
All right, i see the graph, and it looks like this, y versus t.
00:36
And one of them is going like this, such that this.
00:41
This is t sub s and t sub s is two seconds.
00:51
The other one is going down like this, but i can definitely read off the graph that it's divided into eight parts.
01:11
So this t sub s is divided into eight parts like that.
01:20
So then it goes one more over.
01:24
So it goes over another two -eighths.
01:29
Two -eighths.
01:32
So if it goes over another two -eighths, then this time, which i'll call t -sub -2.
01:44
And you know what? i'm going to call this t -sub -1.
01:48
T -sub -2 is going to be 2 .28s.
01:56
So that would be one -fourth, which is two, five seconds.
02:00
And so i'm going to call this t -s -1, like i said.
02:05
Okay.
02:12
So what's the speed of apple 2? well, let's think about apple 1 first.
02:26
Apple 1 is dropped.
02:29
So v squared equals v squared.
02:41
Initial squared minus 2g times the height that it was dropped from.
03:10
I don't see any indication of height on the graph, but it's thrown from the same height.
03:28
So we're saying that right here is h.
03:32
It's the same height.
03:35
Okay.
03:38
So, v squared equals v initial squared minus 2gh.
03:51
Okay, but the first apple is dropped with no initial velocity.
03:57
So v squared equals 2gh.
04:04
So v at the end is 2gh.
04:18
Okay, we also know two seconds.
04:24
So v equals v initial minus gt.
04:34
So v at the end, since v initial is zero, is going to equal negative gt, and we know t is two.
04:59
So v would be 2g in the negative direction at the end.
05:09
So i'm going to put this in a calculator.
05:12
G equals 9 .81.
05:21
T1 is 2 seconds.
05:26
So v at the end equals negative gt 1.
05:41
Negative gt1...